Sewing machine with feed wheel feeding



Jan. 1, 1963 R. REEBER SEWING MACHINE WITH FEED WHEEL FEEDING FiledSept. 12, 1960 I/VVENTOR Rudolf R5585}? 3,7i,tl89 SEWING MACHINE WlTHFEED WHEEL FEEQING Rudolf Reeber, Kaiserslautern, Pfalz, Germany,assrgnor to G. M. Pfat'f A.-G., ltaiserslautern, Pfalz, Germany Filedept. 12, 196i}, Ser. No. 55,376 Claims priority, application Germanydept. 19, 1959 3 (Ilairns. (6111. 112-114) The invention relates to asewing machine provided with feed wheel feeding means and a drivenroller foot.

For sewing together layers of material it is desirable that they aresupplied to the sewing area at the same velocity without there being anymovement of the individual layers of material relative to one anotherduring the sewing operation. Furthermore, it is desirableto provide goodsupervision at the area of sewing as well as the possibility of sewingsharp curves and obtaining reliable guiding of the material. it has beenattempted to attain these features with the aid of feeding mechanismswhich feed the material along its bottom side by means of a feed wheeland along its top side by means of a roller foot which is driven insynchronism with the feed wheel.

If there are elevations in the material being sewn, over which it isnecessary to sew or in changing over from one thickness of material tothe other, there arise difiiculties in that the roller foot and the feedwheel must cover paths of different length. This results in that the onelayer of material is displaced with respect to the other layer.

'It is an object of the invention to provide for the feed wheel and theroller foot being both driven in such a manner that differences betweenthe circumferential paths of the two feed wheels during the sewingoperation are automatically compensated.

in accordance with the invention, this object is achieved in that adifferential gear of a type known per se is arranged between a commongear mechanism for the stitch length and the drive shafts for the feedwheel and for the roller foot.

it is particularly advantageous to arrange the differential gearcoaxially with the shaft of the feed wheel, for in this manneradditional transfer elements are eliminated.

Further objects of the invention and details of the advantages attainedthereby will become apparent from the following description of anembodiment of the new drive means which is illustrated in the drawing.

The clrawin shows an elevational view of the sewing machine partly incross section to expose the parts which are essential for the operation.

A differential gear assembly 2 is provided below the work plate 1 of thesewing machine by way of which a feed wheel 3 and a spring biased rollerfoot 4, such as known per so, are driven.

The differential transmission 2 comprises two intermediate bevel gears5, 6, a shackle member 7 and two drive pinions 8, 9. The shackle 7 has ahub 10 and rotatably supports the two bevel gears 5, 6 and is rotatablyjournalled on a shaft 11 which supports the pinion 9.

The differential 2 is driven from an adjustable transmission 12 of knownconstruction by way of a shaft 13 carrying a toothed gear 14 whichmeshes with a toothed gear 15 provided around the hub 10 on the shackle7.

The differential 2 transmits the driving forces to the feed wheel 3 byway of the pinion gear 8 and shaft 16 and the pinion gear 9 on shaft 11transmits the driving forces to the roller foot 4 by way of a pair ofbevel gears 17, a shaft 18 journalled in the standard of the machine, apair of bevel gears 19, a shaft 213 journalled in the horizontal machinearm, a pair of bevel gears 21, a shaft 22 projecting downwardly out ofthe machine head and a :ifillfih Patented Jan. ll, 19G?) l he pair ofbevel gears 23, one of which is on the roller foot 4.

The setting of the transmission 12 is effected by means of bars 24, 25associated with the adjusting lever 26. By these means the speed ofrotation of the shaft 13 is changed and thus the velocity of feed of thefeed wheel 3 and of the roller foot 4 which determines the stitchlength.

The feeding mechanism operates in the following manner:

The two feed wheels, i.e., the wheel 3 and the roller foot 4 engage thematerial at their rolling point and advance the material between them.If the material has elevations over which it is necessary to sew, forexample, transversely disposed strips of material, pleats, hem seams,decorative trimming as on shoes or the like, then the circumference ofthe wheel which feeds on the side of the material on which the elevationexists must, in order to climb over the elevation, move over a longerpath than the wheel or roller which engages on the side opposite to thatwhere the elevation is located, i.e on. the fiat side of the material.When an elevation encounters the circumference of a feed wheel, thewheel is engaged at one place along its circumference which has not asyet fully reached the normal rolling point so that the particular feedwheel on encountering an elevation contacts the material in two places,the rolling point being one, and the starting place of the elevation theother point of contact.

However, the feed wheel is not yet able at the starting point totransmit feeding force to the material because the location opposite thestarting place likewise has not yet arrived at the rolling point, sothat the material in this location is not yet subjected on both sides tothe spring pressure acting on the roller foot. Therefore the advancingof the material continues to take place at the rolling point of the feedwheels in a manner that the material at the starting point is forcedaway in the direction of the feed wheel which engages the even side ofthe material until the place on the opposite side of the starting pointcomes in contact with the wheel which engages there. Now the materialhas located itself completeiyat its even side from the rolling point tothe place opposite the starting point onto the circumference of the feedwheel which is effective there, while the feed wheel in engagement withthe elevation engages only at the rolling point. To enable feeding thematerial having the elevation between the feed wheels the spring loadedroller foot 4 must be raised an amount equal to the thickness of theelevation. The raising of the roller foot requires an increased feedingforce and that is transmitted or applied to the material by the two feedwheels in proportion to their engagement planes. Since the engagementplane of the material at the feed wheel on the even side of the materialis always the greater, that wheel also takes over the greater part ofthe feeding forces. However, if a larger feeding force is taken awayfrom this feed wheel, then the opposite force acting on it in the areaof contact with the material is greater than that of the feed wheelengaging the elevation. As soon as the differential opposite force actson the feed wheels, the differential 2 becomes effective in a knownmanner, decreasing the circumferential speed of the wheel acting on theeven side of the material and increasing the circumferential velocity ofthe feed wheel which climbs over the elevation.

Together with the differing circumferential velocities thus developedthe circumferential paths of the feed wheels change likewise, so thatthe feed wheel climbing the elevation can cover the greater feeding pathat its location without compensating operations by the operator.However, the reducing of the circumferential velocity of the feed wheelacting on the even side of the material (9 effects a decrease in thematerial feed due to the decreased circumferential path, thus decreasingthe stitch length while sewing over elevations. This decrease, however,is so negligible that the over-all picture of the seam has an evenappearance.

As used in the claims the terms feed wheel drive shaft and roller footdrive shaft refer to shaft 16 to which the feed wheel is directlyconnected and to the shaft 11 which is connected to the roller foot byintermediary gears and shafts.

Having now described my invention with reference to the embodimentillustrated in the drawing, I do not wish to be limited thereto, butWhat I desire to protect by Letters Patent of the United States is setforth in the appended claims.

1. In a sewing machine of the type provided with a feed wheel and adriven roller foot and having a feed wheel drive shaft and a roller footdrive shaft, and an adjustable transmission for the stitch lengthincluding a common drive shaft, a differential gear means including I ashackle member having a driving connection with said common drive shaftand rotatably supporting a pair of bevel gears, a pinion secured to saidfeed wheel d rive shaft and a pinion secured to said roller foot driveshaft, said pair of bevel gears meshing with said pinions and beingoperative to permit differential movement of said feed wheel drive shaftand of said roller foot drive shaft.

2. In a sewing machine of the type provided with a feed wheel and adriven roller foot and having a feed wheel drive shaft and a roller footdrive shaft, and an adjustable transmission for the stitch lengthincluding a common drive shaft, a differential gear means including ashackle member having a driving connection With said common drive shaftand rotatably supporting a pair of bevel gears, a pinion secured to saidfeed Wheel drive shaft and a pinion secured to said roller foot driveshaft,

said pair of bevel gears meshing with said pinions and being operativeto permit differential movement of said feed wheel drive shaft and ofsaid roller foot drive shaft, said shackle member having a hubpresenting a toothed gear and said common shaft having a gear meshingwith said toothed gear.

3. In a sewing machine of the type provided with a feed wheel and adriven roller foot and having a feed wheel drive shaft and a roller footdrive shaft, and an adjustable transmission for the stitch lengthincluding a common drive shaft, a differential gear means including ashackle member having a driving connection with said common drive shaftand rotatably supporting a pair of bevel gears, a pinion secured to saidfeed wheel drive shaft and a pinion secured to said roller foot driveshaft, said pair of bevel gears meshing with said pinions and beingoperative to permit differential movement of said feed wheel drive shaftand of said roller foot drive shaft, said shackle member having a hubpresenting a toothed gear and said common shaft having a gear meshingwith said toothed gear, said feed wheel being disposed endwise of saidfeed Wheel drive shaft below said machine head and in said base and saidroller foot being supported below said machine head proximate said feedwheel above said base for cooperation with said feed wheel and beingconnected to said roller foot drive shaft by intermediate shafts andgears carried by said machine head, arm and standard.

References iterl in the file of this patent UNITED STATES PATENTS l I i

1. IN A SEWING MACHINE OF THE TYPE PROVIDED WITH A FEED WHEEL AND ADRIVEN ROLLER FOOT AND HAVING A FEED WHEEL DRIVE SHAFT AND A ROLLER FOOTDRIVE SHAFT, AND AN ADJUSTABLE TRANSMISSION FOR THE STITCH LENGTHINCLUDING A COMMON DRIVE SHAFT, A DIFFERENTIAL GEAR MEANS INCLUDING ASHACKLE MEMBER HAVING A DRIVING CONNECTION WITH SAID COMMON DRIVE SHAFTAND ROTATABLY SUPPORTING A PAIR OF BEVEL GEARS, A PINION SECURED TO SAIDFEED WHEEL DRIVE SHAFT AND A PINION SECURED TO SAID ROLLER FOOT DRIVESHAFT,